As is known in the art, an electrostatic discharge (ESD) event is the sudden flow of electricity between two electrically charged objects, typically caused by contact, an electrical short, or dielectric breakdown. The ESD event can deliver a large amount of energy to different portions of an integrated circuit (IC), damaging various circuitry within the IC.
To provide protection from ESD events, IC's may use a grounded gate N-type metal-oxide-semiconductor (GGNMOS) clamp. However, the voltage operating range of a particular GGNMOS clamp is limited based on the properties of the different layers within the GGNMOS clamp. For example, the maximum direct current (DC) voltage that can be sustained by the GGNMOS clamp is limited to the breakdown between the drain and gate terminals. GGNMOS clamps include a gate oxide layer having a degradation factor that limits the voltage operating range of the GGNMOS clamps. Thus, due to the gate oxide degradation, the maximum sustained DC voltage between the drain and gate terminals is limited and thus, the voltage operating range of the GGNMOS is limited. For example, a GGNMOS structure having a 90 A gate oxide is limited to a 3.6V operating range.